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Tetrazolo triazine

Reduction of the tetrazolo-triazines (327) with sodium borohydride in methanol afforded the... [Pg.218]

Tetrazolo[5,1 -6][ 1,2,4]triazin-3-ones synthesis, 3, 392 Tetrazolyl radicals oxidation, 5, 60 Tetrazolyl ylides structure, 5, 793 Tetrenolin occurrence, 4, 706 Tetrodotoxin... [Pg.857]

No tetrazolo species were found in solutions of 2,4,6-triazido-s-triazine and 2,4,6-triazidopyrimidine (79UKZ975). [Pg.280]

Naphtho analogues, naphtho[2,l-e]tetrazolo[l,5-6][l,2,4]triazine, naph-tho[l,2-e]tetrazolo[l,5-b][l,2,4]triazine, and naphtho[2,3-e]tetrazolo[l,5-Zj][1, 2,4]triazine, were prepared (82JOC3168 84JOC3199) by cyclization of the respective hydrazine with sodium nitrite in acetic acid or by azide displacement of a leaving group. Elucidation of the site of annulation of the tetrazole ring was accomplished by X-ray analysis and l3C-NMR spectroscopy (Scheme 189). [Pg.150]

The presence of a 5-oxo group in the 1,2,4-triazines, as in 3-hydrazino-2,5-dihydro-5-oxo[l,2,4]triazines, does not alter the direction of cycliza-tion by the action of nitrous acid. The initial products are azido compounds 1016, which can cyclize spontaneously to tetrazolo[l,5-b][l,2,4]triazines 1017 (77JHC1221, 77JOC1866) rather than the previously reported isomeric structure. On the other hand, when the cyclization onto N-2 is impossible, as in derivative 1018, the azidotetrazolo equilibrium 1018 1019 exists (76JOC2860 77JOC1866). It exists in the solid state at least as the tetrazole derivative (Scheme 190). [Pg.151]

Alternatively, cyclocondensation of 1,5-diaminotetrazole 1024 with gly-oxal and substituted glyoxals produced tetrazolo[ 1,5-6][l, 2,4]triazine 1025 (88JOC5371), which can be reduced to 7,8-dihydro derivative 1026 using Pd/C as a hydrogenating catalyst, but NaBH4 gave 5,6,7,8-tetrahydro derivative 1027. [Pg.152]

Pyridine A-oxides were converted to tetrazolo[l,5-a]pyridines 172 by heating in the presence sulfonyl or phosphoryl azides and pyridine in the absence of solvent <06JOC9540>. 3-R-5-Trinitromethyltetrazolo[l,5-a]-l,3,5-triazin-7-ones 173 have been prepared from the alkylation of 5-trinitromethyltetrazolo[l,5-a]-l,3,5-triazin-7-one silver salt with different alkylation agents <06CHE417>. The use of 2-fluorophenylisocyanide in the combinatorial Ugi-tetrazole reaction followed by a nucleophilic aromatic substitution afforded tricylic tetrazolo[l,5-a]quinoxaline 174 in good yields and with high diversity <06TL2041>. [Pg.234]

Condensed tetrazolo[ 1,5-aJ [ 1,3,5Jtriazin-7-ones have been prepared from the corresponding 4-azido-l,3,5-triazines <06CHE1051>. [Pg.423]

Cyclization of 776 with ortho-esters gave (83JOC1628) [l,2,4]triazolo-[4,3-fc]pyrimido[5,4-< ][ 1,2,4]triazines 777, whereas reaction with sodium nitrite afforded the corresponding tetrazolopyrimidotriazine 778.3-Azido-pyrimido[4,5-e][l, 2,4]triazine 779 exists in a cyclic form as tetrazolo derivative 780, as shown by X-ray analysis (86KGS114). In solution the position of the 779 780 equilibrium depended on temperature and solvent. Higher temperatures favored 779. Azido compound 779 predominated in water, and tetrazolo compound 780 predominated in pyridine. Addition of sodium azide to the aqueous solution shifted the equilibrium toward 780. The... [Pg.307]

Ring-opening reactions of some tetrazolo[5,l-r-][l,2,4]triazines have been reported by Chupakhin et al. <2005IZV713>, as shown in Scheme 3. [Pg.911]

A series of functionalizations of the ring system tetrazolo[l,5- ][l,2,4]triazine 1 have been reported by Rusinov et al. [Pg.912]

All synthetic works belonging to this section relate, with one exception, to the preparation of tetrazolo[l,5-A -[l,2,4]triazines. Although the final outcome of this outstanding work as published by Chupakhin et al. <2005IZV713> is also formation of this ring system, the reaction pathway actually involves a ring transformation reaction. The interesting result is summarized in Scheme 10. [Pg.915]

The reaction sequence starts from tetrazolyldiazonium salt 42 prepared from aminotetrazole 41 by diazotation. This compound when reacted with arylformylacetonitrile 43 leads to the intermediate formation of the condensation product 44, which easily undergoes ring closure to 45. This tetrazolo[5,l-z][l,2,4]triazine compound, however, forms an equilibrium with the valence bond isomeric azide 46, which can participate in a different ring closure than the reverse route, and yields the tetrazolo[l,5-A][l,2,4]triazine product 47. The reaction was carried out with a series of various aryl derivatives and proceeded in good to excellent yields (68-87%). [Pg.915]

Other cyclizations to give tetrazolo[l,5-7][l,2,4]triazines published in recent years basically follow the established procedures discussed earlier in CHEC-II(1996) < 1996CHEC-II(8)499> and belong to two categories (1) reaction of 1,5-diaminotetrazole 42 with ct-dioxo reagents, and (2) reaction of a 3-hydrazino[l,2,4]triazine derivative with nitrous acid. [Pg.916]

Synthesis of an interesting anionic derivative of the ring system tetrazolo[l,5-tf][l,3,5]triazine was reported by Fedorov et al. <2005KGS259> the ring-closure reaction is shown in Scheme 11. [Pg.916]

Azido-2H-l,2,4-triazin-3-ones (56a) also cyclize to give the tetrazolo[5,l-d]-[l,2,4]triazin-3-ones (56b) (71RRC135, 71RRC311). Nitrosation of 3-amino-6-hydrazino-l,2,4-triazin-5-one (57) affords a compound which exhibits an intense absorption at 2140cm-1, showing that the 6-azido tautomer (58a) was isolated. When this compound was stirred for a few minutes in a polar solvent it quantitatively formed the tetrazole tautomer (58b) (79JHC555). [Pg.392]

N-Oxidation of 3-azido-l,2,4-triazines at either N-l or N-2 destabilizes the bicyclic compounds so that only the monocyclic azide tautomers (59, 60) are observed (77JHC1221). 3-Azido-l,2,4-benzotriazine was also found to exist as the azido tautomer (61b) in solution, but in the crystalline state it favoured the tetrazolo[5,l-c][l,2,4]benzotriazine structure (61a) (73JHC575). In DMSO the third isomer, the tetrazolo[l,5-b ]-fused compound (61c), was detected in small amount (10%) by 13C NMR spectroscopy (79JOC1823). Solvent and... [Pg.392]


See other pages where Tetrazolo triazine is mentioned: [Pg.150]    [Pg.142]    [Pg.150]    [Pg.142]    [Pg.857]    [Pg.274]    [Pg.41]    [Pg.41]    [Pg.41]    [Pg.41]    [Pg.41]    [Pg.41]    [Pg.148]    [Pg.149]    [Pg.152]    [Pg.153]    [Pg.423]    [Pg.909]    [Pg.909]    [Pg.909]    [Pg.915]    [Pg.916]    [Pg.917]    [Pg.656]    [Pg.176]    [Pg.392]    [Pg.857]    [Pg.966]    [Pg.966]    [Pg.261]   
See also in sourсe #XX -- [ Pg.423 ]

See also in sourсe #XX -- [ Pg.423 ]




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Tetrazolo-triazines, reduction

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